U.S. patent number 9,559,432 [Application Number 14/371,369] was granted by the patent office on 2017-01-31 for antenna control system and multi-frequency shared antenna.
This patent grant is currently assigned to COMBA TELECOM SYSTEM (CHINA) LTD.. The grantee listed for this patent is Comba Telecom System (China) Ltd.. Invention is credited to Feifei Jia, Peitao Liu, Shan qiu Sun.
United States Patent |
9,559,432 |
Sun , et al. |
January 31, 2017 |
Antenna control system and multi-frequency shared antenna
Abstract
A multi-frequency shared antenna comprises a low frequency
radiation array and a first high frequency radiation array both of
which are disposed on a reflection plate and provided with power by
different feeding networks. The first high frequency radiation
array comprises a number of high frequency radiation units, at
least partial high frequency radiation units are arranged on a same
axis which overlaps one of two axes of the low frequency radiation
array, in all high frequency radiation units arranged on said axis,
at least partial high frequency radiation units are nested with the
low frequency radiation units arranged on the same axis, and the
orthogonal projection area of these nested high frequency radiation
units on the reflection plate falls within the orthogonal
projection area of the corresponding low frequency radiation units
on the same reflection plate.
Inventors: |
Sun; Shan qiu (Gaungzhou,
CN), Jia; Feifei (Gaungzhou, CN), Liu;
Peitao (Guangzhou, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Comba Telecom System (China) Ltd. |
Guangzhou, Guangdong Province |
N/A |
CN |
|
|
Assignee: |
COMBA TELECOM SYSTEM (CHINA)
LTD. (Guangzhou, Guangdong Province, CN)
|
Family
ID: |
48207022 |
Appl.
No.: |
14/371,369 |
Filed: |
December 28, 2012 |
PCT
Filed: |
December 28, 2012 |
PCT No.: |
PCT/CN2012/087783 |
371(c)(1),(2),(4) Date: |
July 09, 2014 |
PCT
Pub. No.: |
WO2013/104260 |
PCT
Pub. Date: |
July 18, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20150009078 A1 |
Jan 8, 2015 |
|
Foreign Application Priority Data
|
|
|
|
|
Jan 13, 2012 [CN] |
|
|
2012 1 0012047 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01Q
21/0006 (20130101); H01Q 5/307 (20150115); H01Q
21/06 (20130101); H01Q 19/108 (20130101); H01Q
21/24 (20130101); H01Q 21/26 (20130101); H01Q
5/42 (20150115) |
Current International
Class: |
H01Q
21/26 (20060101); H01Q 19/10 (20060101); H01Q
21/06 (20060101); H01Q 5/42 (20150101); H01Q
21/00 (20060101); H01Q 5/307 (20150101); H01Q
21/24 (20060101) |
Field of
Search: |
;343/727 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Levi; Dameon E
Assistant Examiner: Davis; Walter
Attorney, Agent or Firm: Powell; John W.
Claims
The invention claimed is:
1. A multi-frequency shared antenna, comprising a low frequency
radiation array and a first high frequency radiation array both of
which are disposed on a reflection plate, wherein, the low
frequency radiation array comprises a plurality of low frequency
radiation units axially arranged on at least two parallel axes, and
said low frequency radiation units on said two axes are misaligned
along a direction orthogonal to these axes; the pitch between said
two axes of the low frequency radiation array is smaller than or
equal to a half wavelength of the low frequency radiation array at
its highest working frequency point, and it is also greater than or
equal to a half wavelength of the high frequency radiation array at
its highest working frequency point; each low frequency radiation
unit comprises two pairs of symmetrical dipoles arranged such that
their polarization is orthogonal to each other, and two symmetrical
dipoles of one pair of symmetrical dipoles of at least one low
frequency radiation unit of the low frequency radiation array have
different feed-in power settings; the first high frequency
radiation array comprises a plurality of high frequency radiation
units, at least some of the high frequency radiation units are
arranged on an axis which overlaps one of said two parallel axes of
the low frequency radiation array, in all high frequency radiation
units arranged on said axis which overlaps one of said two parallel
axes, at least one high frequency radiation units is nested with a
corresponding low frequency radiation unit and an orthogonal
projection area of each of the at least one nested high frequency
radiation unit on the reflection plate falls within the orthogonal
projection area of each corresponding low frequency radiation unit
on the same reflection plate.
2. The multi-frequency shared antenna according to claim 1, wherein
for said at least two parallel axes, any two adjacent low frequency
radiation units arranged on different axes form a group, in four
symmetrical dipoles with the same polarization of the group, a
symmetrical axis is defined between a first axis and a second axis,
symmetrical dipoles close to said symmetrical axis have the same or
substantially same feed-in power, symmetrical dipoles away from
said symmetrical axis have the same or substantially same feed-in
power, and the feed-in power of the dipoles close to the
symmetrical axis is greater than that of the dipoles away from the
symmetrical axis.
3. The multi-frequency shared antenna according to claim 1, wherein
a symmetrical axis is defined between a first and second axes of
said at least two parallel axes, the sum of feed-in power of the
adjacent symmetrical dipoles located at left of the symmetrical
axis is identical to or substantially identical to that of the
adjacent symmetrical dipoles located at right of the symmetrical
axis, the sum of feed-in power of the symmetrical dipoles located
at left of the symmetrical axis and distanced away from each other
is identical to or substantially identical to that of the
symmetrical dipoles located at right of the symmetrical axis and
distanced away from each other, and the sum of the former is larger
than that of the latter.
4. The multi-frequency shared antenna according to claim 1, further
comprising a second high frequency radiation array, the second high
frequency radiation array comprises a plurality of high frequency
radiation units which are at least partially arranged on a same
axis, and the axis of the first high frequency radiation array is
adjacent and parallel to the axis of the second high frequency
radiation array.
5. The multi-frequency shared antenna according to claim 4, wherein
the axis of the second high frequency radiation array overlaps one
axis of the low frequency radiation array, at least one of said
high frequency radiation units of the second high frequency
radiation array is nested with a corresponding low frequency
radiation unit, and an orthogonal projection area of each of the at
least one nested high frequency radiation unit on the reflection
plate falls within the orthogonal projection area of each
corresponding low frequency radiation unit on the same plate.
6. The multi-frequency shared antenna according to claim 5, wherein
at one end of the symmetrical axis of the axes of the first and
second high frequency radiation arrays, the plurality of low
frequency radiation units of the low frequency radiation array are
distributed along said symmetrical axis.
7. The multi-frequency shared antenna according to claim 5, further
comprising a third and fourth high frequency radiation arrays
located parallel to each other, an axis of the third high frequency
radiation array overlaps an extension line of the axis of the first
high frequency radiation array, and an axis of the fourth high
frequency radiation array overlaps an extension line of the axis of
the second high frequency radiation array, in the ranges of the
extension lines where the third and fourth high frequency radiation
arrays are located, there are low frequency radiation units for
nesting with the third and fourth high frequency radiation arrays,
the orthogonal projection area of the nested high frequency
radiation units on the reflection plate falls within the orthogonal
projection area of corresponding low frequency radiation units on
the same plate.
8. The multi-frequency shared antenna according to claim 5, further
comprising third and fourth high frequency radiation arrays
parallel to the first and second high frequency radiation arrays,
respectively, and a second low frequency radiation array, the
second low frequency radiation array is assembled with the third
and fourth high frequency radiation arrays and an axis thus formed
is parallel to the aforementioned axes.
9. The multi-frequency shared antenna according to claim 1, wherein
some of the high frequency radiation units of the first high
frequency radiation array are arranged along a third axis; and the
high frequency radiation units of the first high frequency
radiation array arranged on respective axes are misaligned among
each other along a direction orthogonal to the axes.
10. The multi-frequency shared antenna according to claim 1,
wherein both the low frequency radiation array and the first high
frequency radiation array are distributed on two axes, one axis of
the low frequency radiation array overlaps one axis of the first
high frequency radiation array, and another axis of the low
frequency radiation array and another axis of the first high
frequency radiation array are symmetrical about the overlapped
axis.
11. The multi-frequency shared antenna according to claim 1,
wherein there is no interference between an orthogonal projection
on the reflection plate of a radiation arm of a symmetrical dipole
of any low frequency radiation unit and that of a symmetrical
dipole of any high frequency radiation unit.
12. The multi-frequency shared antenna according to claim 1,
wherein along an orthogonal projecting direction towards the
reflection plate, the pitch between two adjacent axes of the low
frequency radiation array is smaller than or equal to the biggest
orthogonal projection size of an individual low frequency radiation
unit arranged on these axes.
13. The multi-frequency shared antenna according to claim 1,
wherein along the axial direction of the low frequency radiation
array, some low frequency radiation units with odd locations are
arranged on an axis of the low frequency radiation array, while
some low frequency radiation units with even locations are arranged
on another axis thereof.
14. The multi-frequency shared antenna according to claim 1,
wherein along the axial direction of the low frequency radiation
array, some low frequency radiation units with discrete locations
are arranged on an axis of the low frequency radiation array, while
some low frequency radiation units with continuous locations are
arranged on another axis thereof.
15. The multi-frequency shared antenna according to claim 1,
wherein the high frequency radiation units and/or low frequency
radiation units are of printed planar radiation unit or surface
mounted dipole.
16. The multi-frequency shared antenna according to claim 1,
wherein the biggest diameter of the low frequency radiation unit is
smaller than 150 mm.
17. A multi-frequency shared antenna, comprising a reflection
plate, a first frequency radiation array and a second frequency
radiation array, wherein, the first frequency is higher than the
second frequency, the second frequency radiation array has a first
axis and a second axis substantially parallel in a vertical
direction to the first axis; the second frequency radiation array
comprise at least three second frequency radiation units located on
the first and second axes, at least one of the second frequency
radiation units is provided on each axis, three second frequency
radiation units are misaligned among each other in a direction
orthogonal to the axial direction; the first frequency radiation
array comprise at least one first frequency radiation unit located
on the first axis.
Description
RELATED APPLICATIONS
This application is a U.S. National Stage of international
application number PCT/CN2012/087783 filed Dec. 28, 2012, which
claims the benefit of the priority date of Chinese Patent
Application CN 201210012047.0, filed on Jan. 13, 2012, the contents
of which are herein incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to field of mobile communication
antenna and more particularly, relates to a multi-frequency shared
antenna and antenna control system based on said multi-frequency
shared antenna.
BACKGROUND OF THE INVENTION
With increase of mobile communication network standards, to save
sites and location, reduce difficulty of estate management
coordination, and decrease investment cost, multi-frequency shared
antenna sharing a common site and location is eventually becoming a
first choice for operators in networking business.
Currently in this industry, two constructions are mainly employed
to multi-frequency shared antennae array. One solution is coaxial
nesting as denoted in FIG. 1. According to this solution, a low
frequency radiation unit 1a and a high frequency radiation unit 2a
are coaxially arranged on a same axis 4a of a reflection plate 3a.
Another solution is side by side adjoining solution as shown in
FIG. 2. In this solution, a low frequency radiation unit 1b and a
high frequency radiation unit 2a are separately disposed on two
adjacent axes 4b and 5b of a reflection plate 3b. Needless to say,
the axial nesting scheme significantly has smaller antenna width
and windward area than side by side scheme and accordingly, it gets
much favor from clients.
It has been found in practice that coaxial nesting technique shown
in FIG. 1 suffers from certain limit during use and there are at
least two drawbacks.
At first, in case that pitch between low frequency radiation units
1a arranged in line with the high frequency radiation units 2a is
not integer times of pitch between high frequency radiation units
2a, in an orthogonal projection area formed by orthogonally
projecting onto the reflection plate, radiation arms of the low
frequency radiation unit 1a, which is enable to nest with the high
frequency radiation unit 2a, will be over the high frequency
radiation unit 2a and overlap and cross with the same (as shown in
FIG. 3, the low frequency radiation unit 1c crosses and overlaps
with the high frequency radiation unit 2c), thus causing severe
interference to high frequency radiation array formed by said high
frequency radiation unit 2a, and greatly increasing difficulty in
design of high frequency radiation array radiation characteristics.
For example, when coaxial nesting technique applies to
multi-frequency shared electrically adjustable antenna working at
frequency of 790.about.960 MHz and 1710.about.2690 MHz, to make
balance between gain and parameters such as electrically
down-tilted upper side-lobes, pitch range of low frequency
radiation array is normally from 250 mm to 300 mm, while pith range
of high frequency radiation array is normally from 105 mm to 115
mm. No matter what sort of array pitch is selected from above
ranges for high and low frequency, when all the high frequency
radiation units 2b and low frequency radiation units 1b are
coaxial, radiation arms of some low frequency radiation units 1b
will locate over the high frequency radiation units 2b, thereby
causing severe interference to high frequency radiation units 2b,
and greatly increasing difficulty in design of high frequency
radiation array radiation characteristics. Attempts have been made
to overcome this problem by reducing projection area of the low
frequency radiation units 1b. However, this will also increase
half-power beam width in horizontal plane of the low frequency
radiation units 1b and therefore no desired results may be
obtained.
Secondly, it may be applied into triple electrically adjustable
antenna constructed of a low frequency radiation array and two
identical high frequency radiation arrays. Regarding this point,
there are two prior art solutions. One is shown in FIG. 4 where a
group of high frequency radiation arrays is added to an antenna
along a vertical direction. The shortcoming of this solution lies
in substantial increase in antenna length. Further, transmission
loss as well as antenna gain loss is increased due to lengthening
of main feeder line of upper high frequency radiation array. A
second solution is illustrated in FIG. 5 where a group of high
frequency radiation arrays is added to an antenna at a lateral side
thereof. This solution suffers from shortcoming such as substantial
increase of antenna width. In addition, all the low frequency
radiation arrays are distributed at a side of the high frequency
radiation arrays. Due to dramatic asymmetry between left and right
radiation boundary of the low and high frequency radiation arrays
together with cross-interference between the two arrays, problem
such as direction deflection of horizontal plane beam of the two
arrays and cross polarization ratio deterioration arises. This
results in increased difficulty in design.
SUMMARY OF THE INVENTION
One object of the invention is to provide a multi-frequency shared
antenna capable of maintaining reasonable antenna size and good
electric characteristics.
Another object of the invention is to provide an antenna control
system for more suitably using the multi-frequency shared antenna
in field.
To achieve above objects, there is provided a technical solution as
follows.
A multi-frequency shared antenna according to the invention
comprises a low frequency radiation array and a first high
frequency radiation array both of which are disposed on a
reflection plate and provided with power by different feeding
networks, wherein,
the low frequency radiation array comprises a number of low
frequency radiation units axially arranged on at least two parallel
axes, and said low frequency radiation units on said two axes are
misaligned along a direction orthogonal to these axes;
the pitch between said two axes of the low frequency radiation
array is smaller than or equal to half wavelength of the low
frequency radiation array at its highest working frequency point,
and it is also greater than or equal to half wavelength of the high
frequency radiation array at its highest working frequency
point;
each low frequency radiation unit comprises two pairs of
symmetrical dipoles arranged such that their polarization is
orthogonal to each other, and two symmetrical dipoles of one pair
of symmetrical dipoles of at least one low frequency radiation unit
of the low frequency radiation array have different feed-in power
setting;
the first high frequency radiation array comprises a number of high
frequency radiation units, at least partial high frequency
radiation units are arranged on a same axis which overlaps one of
two axes of the low frequency radiation array, in all high
frequency radiation units arranged on said axis, at least partial
high frequency radiation units are nested with the low frequency
radiation units arranged on the same axis, and the orthogonal
projection area of these nested high frequency radiation units on
the reflection plate falls within the orthogonal projection area of
the corresponding low frequency radiation units on the same
reflection plate.
According to one embodiment of the invention, for the two axes on
which the low frequency radiation array locates, any two adjacent
low frequency radiation units arranged on different axes form a
group, in four symmetrical dipoles with the same polarization of
the group, a symmetrical axis is defined between a first axis and a
second axis, symmetrical dipoles close to said symmetrical axis
have the same or substantially same feed-in power, symmetrical
dipoles away from said symmetrical axis have the same or
substantially same feed-in power, and the feed-in power of the
dipoles close to the symmetrical axis is greater than that of the
dipoles away from the symmetrical axis.
According to another embodiment of the invention, a symmetrical
axis is defined between a first and second axes of two axes
occupied by the low frequency radiation array, the sum of feed-in
power of the adjacent symmetrical dipoles located at left of the
symmetrical axis is identical to or substantially identical to that
of the adjacent symmetrical dipoles located at right of the
symmetrical axis, the sum of feed-in power of the symmetrical
dipoles located at left of the symmetrical axis and distanced away
from each other is identical to or substantially identical to that
of the symmetrical dipoles located at right of the symmetrical axis
and distanced away from each other, and the sum of the former is
larger than that of the latter.
According to another embodiment of the invention, the antenna
further comprises a second high frequency radiation array powered
by other feeding network, the second high frequency radiation array
comprises a number of high frequency radiation units which are at
least partially arranged on a same axis, and the axis of the first
high frequency radiation array is adjacent and parallel to that of
the second high frequency radiation array.
According to another embodiment of the invention, the axis of the
second high frequency radiation array overlaps one axis of the low
frequency radiation array, at least partial high frequency
radiation units of the second high frequency radiation array are
nested with the low frequency radiation units arranged on the same
axis, and the orthogonal projection area of these nested high
frequency radiation units on the reflection plate falls within the
orthogonal projection area of corresponding low frequency radiation
units on the same plate.
According to another embodiment of the invention, at one end of the
symmetrical axis of the axes of the first and second high frequency
radiation arrays, the plural low frequency radiation units of the
low frequency radiation array are distributed along said
symmetrical axis.
According to another embodiment of the invention, the antenna
further comprises a third and fourth high frequency radiation
arrays located parallel to each other and powered by separate
feeding networks, an axis of the third high frequency radiation
array overlaps an extension line of the axis of the first high
frequency radiation array, and an axis of the fourth high frequency
radiation array overlaps an extension line of the axis of the
second high frequency radiation array, in the ranges of the
extension lines where the third and fourth high frequency radiation
arrays located, there are low frequency radiation units for nesting
with the third and fourth high frequency radiation arrays, the
orthogonal projection area of these nested high frequency radiation
units on the reflection plate falls within the orthogonal
projection area of corresponding low frequency radiation units on
the same plate.
According to another embodiment of the invention, the antenna
further comprises a third and fourth high frequency radiation
arrays parallel to the first and second high frequency radiation
arrays respectively and powered by separate feeding networks, and a
second low frequency radiation array powered by separate feeding
network, the second low frequency radiation array is assembled with
the third and fourth high frequency radiation arrays by the manner
aforementioned, and an axis thus formed is parallel to the
aforementioned axes.
According to another embodiment of the invention, part of the high
frequency radiation units of the first high frequency radiation
array are arranged along another axis; and the high frequency
radiation units of the first high frequency radiation array
arranged on respective axes are misaligned among each other along a
direction orthogonal to the axes.
According to another embodiment of the invention, both the low
frequency radiation array and first high frequency radiation array
are distributed on two axes, one axis of the low frequency
radiation array overlaps one axis of the first high frequency
radiation array, and another axis of the low frequency radiation
array and another axis of the first high frequency radiation array
are symmetrical about the overlapped axis.
Preferably, there is no interference between an orthogonal
projection on the reflection plate of a radiation arm of a
symmetrical dipole of any low frequency radiation unit and that of
a symmetrical dipole of any high frequency radiation unit.
Preferably, along an orthogonal projecting direction towards the
reflection plate, the pitch between two adjacent axes of the low
frequency radiation array is smaller than or equal to the biggest
orthogonal projection size of an individual low frequency radiation
unit arranged on these axes.
Preferably, along the axial direction of the low frequency
radiation array, some low frequency radiation units with odd
locations are arranged on an axis of the low frequency radiation
array, while some low frequency radiation units with even locations
are arranged on another axis thereof.
Preferably, along the axial direction of the low frequency
radiation array, some low frequency radiation units with discrete
locations are arranged on an axis of the low frequency radiation
array, while some low frequency radiation units with continuous
locations are arranged on another axis thereof.
Specifically, the high frequency radiation units and/or low
frequency radiation units are of printed planar radiation unit or
surface mounted dipole. The biggest diameter of the low frequency
radiation unit is smaller than 150 mm.
An antenna control system according to a second object of the
invention comprises a multi-frequency shared antenna as described
above, and further comprises a phase shifter for changing phase of
signal provided to the radiation units inside the antenna, the
phase shifter comprises first and second components, and sliding of
the first component relative to the second component results in
phase change of signal passing through the phase shifter.
To realize electrical adjustment per requirement, the system
comprises an electromechanical driving component; the
electromechanical driving component comprises a power control unit,
a motor and a mechanical driving unit; in response to an external
control signal, the power control unit drives the motor to produce
a predefined motion; and through the torque generated by the
mechanical driving unit, the predefined motion of the motor is
applied to the first component so as to realize phase shifting.
Compared to prior art, the present invention has the following good
technical advantages.
Compared to coaxial nesting technical solution in which low
frequency radiation array and high frequency radiation array are
arranged coaxially, in present invention, the low frequency
radiation array is divided into two or more groups distributed on
different axis. Each group comprises one or more low frequency
radiation units. One group is disposed to overlap the axis of the
high frequency radiation array.
In case that pitch among low frequency radiation units arranged on
the same axis is not integer times as great as that of the high
frequency radiation units, interference (overlapping or crossing)
between radiation arms of the low frequency radiation array and
that of the high frequency radiation array in the orthogonal
projection area in the reflection plate is avoided, as would have
occur in above coaxial nesting technical solution, thus low and
high frequency radiation arrays design difficulty is also
reduced.
In the context of treble frequency shared antenna including a low
frequency radiation array and two high frequency radiation arrays
both having the same frequency, at least part of the high frequency
radiation units of the two high frequency radiation arrays are
arranged on two substantially parallel axes, and they overlap with
one axis of the low frequency radiation array respectively. In
addition, at least partial high frequency radiation units on each
axis are nested with the low frequency radiation units on the same
axis. This eliminates gain loss and size increase of the entire
antenna due to direct addition of a high frequency radiation array
along a vertical direction of the antenna as would be in above
coaxial nesting solution.
Compared to another solution in which the low frequency radiation
array and high frequency radiation array re adjoined together, the
low frequency radiation array is divided into two or more groups
distributed on different axis. Each group comprises one or more low
frequency radiation units. One group is disposed to overlap the
axis of the high frequency radiation array. The number of the low
frequency radiation units at one side of the high frequency
radiation array is reduced. At the same time, the number of the
high frequency radiation units at one side of the low frequency
radiation array is also reduced. Left and right asymmetry of the
low and high frequency radiation arrays is also improved.
Correspondingly, horizontal plane beam direction deflection and
cross-polarization ratio are also improved, this further reducing
design difficulty.
Furthermore, in a range smaller than or equal to half wavelength of
the low frequency radiation array at its highest working frequency
point and also larger than or equal to half wavelength of the high
frequency radiation array at its highest working frequency point,
the pitch between at least two axes of the low frequency radiation
array is regulated. This brings better radiation characteristics
such as horizontal plane half power beam width of the
multiple-frequency shared antenna. Additionally, the entire lateral
size (along orthogonal direction) is just smaller than the lateral
size of the low frequency radiation array adjoined the high
frequency radiation array, but larger than the lateral size when
the low frequency radiation array and high frequency radiation
array are nested together.
Moreover, by adjusting signal feed-in power of two symmetrical
dipoles of each polarization of the low frequency radiation unit
and setting radiation diameter of the low frequency radiation
units, desired horizontal plane half power beam width absolute
value is obtained for the low frequency radiation array. Further,
better horizontal plane half power beam width convergence is also
obtained. For example, in frequency range of 790-960 MHz,
horizontal plane half power beam width is within 62.+-.3 degree.
This can't be realized when the low frequency radiation array and
high frequency radiation array are nested together or when the low
frequency radiation array and high frequency radiation array are
adjoined together.
By adjusting power of two symmetrical dipoles of each polarization
of the low frequency radiation unit, vertical plane half power beam
width of the low frequency radiation array is extended. In
addition, due to better horizontal plane half power beam width
convergence, the smallest gain of the low frequency radiation array
working frequency band is still superior than prior art nesting
solution and adjoining solution.
Evidently, the present invention is able to realize sharing of
multiple frequencies antenna in as small as possible size. The
pitch between radiation units no longer results in interference
between the low and high frequency beams. The antenna control
system based on this multiple-frequency shared antenna thus also
bears all advantages described above. This multiple-frequency
shared antenna will make it easy and convenient to locate and trim
low frequency radiation unit during design period.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior art structural view of a dual-frequency shared
antenna employing coaxial nesting technique;
FIG. 2 shows a prior art structural view of a dual-frequency shared
antenna employing adjoining technique;
FIG. 3 shows a prior art structural view of a dual-frequency shared
antenna employing coaxial nesting technique in which radiation arms
of low frequency radiation units locate above high frequency
radiation units, thus resulting in overlapping between dipole arms
in an orthogonal projection area generated by orthogonally
projecting onto a reflection plate;
FIG. 4 shows a prior art structural view of a triple frequency
shared antenna;
FIG. 5 shows another prior art structural view of a triple
frequency shared antenna;
FIG. 6 shows a structural view of a first embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two frequencies
are transmitted;
FIG. 7 shows a structural view of a second embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two frequencies
are transmitted;
FIG. 8 shows a structural view of a third embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two or three
frequencies are transmitted;
FIG. 9 shows a structural view of a fourth embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two or three
frequencies are transmitted;
FIG. 10 shows a structural view of a fifth embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two or three
frequencies are transmitted;
FIG. 11 shows a structural view of a sixth embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two through
five frequencies are transmitted;
FIG. 12 shows a structural view of a seventh embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two through six
frequencies are transmitted; and
FIG. 13 shows a structural view of a eighth embodiment of a
multi-frequency shared antenna according to the invention which is
suitable to be used in application where signals of two frequencies
are transmitted.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in further detail in conjunction
with various embodiments and accompanied drawings.
It is well known that a radiation array (including low frequency
and high frequency radiation array) is intended to transmit
communication signals and is generally constituted by a plurality
of radiation units arranged in matrix in the form of a single or
multiple lines. As to high frequency signals, a high frequency
radiation array is formed by plural high frequency radiation units.
Correspondingly, a low frequency radiation array is formed by
plural low frequency radiation units. Here, in a radiation unit, a
component for transmitting and receiving signals is a symmetrical
dipole of the unit. An electrical component of the symmetrical
dipole is its radiation arm which is supported by a balun of the
symmetrical dipole. In a radiation unit, to improve gain of
polarization diversity receiving, two pairs of symmetrical dipoles
are employed and they are arranged such that their polarization is
orthogonal to each other. Two symmetrical dipoles of each pair of
symmetrical dipoles may have different feed-in power setting. The
radiation unit may be planar and printed on a plate, or it may also
be of a three-dimensional construction. These fundamental concepts
will be referenced throughout all description of various
embodiments of the invention. When the radiation array is installed
on a reflection plate, an orthogonal projection area is formed when
the array is projected toward the reflection plate. FIGS. 6-13 of
the invention will be illustrated with reference to this orthogonal
projection area to clearly show relation along different radiation
arrays.
Please refer to FIG. 6. According to a first embodiment of the
present invention, a multi-frequency shared antenna has a
reflection plate 3 onto which a low frequency radiation array 1 and
a high frequency radiation array 2 are arranged.
The low frequency radiation array 1 is composed of 5 low frequency
radiation units 11-15. In these low frequency radiation units
11-15, from top to bottom, 3 low frequency radiation units 11, 13
and 15 (all have odd reference numerals) are located on a first
axis a1, while 2 low frequency radiation units 12 and 14 (all have
even reference numerals) are located on a second axis a2. The first
and second axes a1 and a2 are parallel with each other. In
addition, in a direction orthogonal to the two adjacent axes a1 and
a2 (that is, horizontal direction in this figure and this also
applies hereinafter), the low frequency radiation units 11-15
located on these axes a1 and a2 respectively are distributed
alternately. In other words, along the orthogonal direction of the
axes a1 and a2, none of the low frequency radiation units on the
axis a1 will be in side by side relation with any one of the low
frequency radiation units on the axis a2. Along a projection
direction orthogonal to the reflection plate 3 (that is, a
direction perpendicular to and facing paper sheet, and the same is
true for followed description), the distance between the first axis
a1 and second axis a2 is smaller than or equal to the largest
orthogonal projection size of an individual low frequency radiation
unit located on these axes a1 and a2. By this way, it is ensured
that the horizontal dimension of the entire antenna is smaller than
that when the low frequency radiation array 1 and high frequency
radiation array 2 are adjoined to each other, though larger than
that when the low frequency radiation array 1 and high frequency
radiation array 2 are nested with each other. On the other hand,
the pitch between the first axis a1 and second axis a2 may be
configured to be less than or equal to half wavelength of the low
frequency radiation array at its highest working frequency point,
and at the same time, larger than or equal to half wavelength of
the high frequency radiation array at its highest frequency point,
thus obtaining balance between antenna size and best electric
performance. Normally, if the two axes a1 and a2 meet the former
pitch setting, they will also meet the latter pitch setting.
The high frequency radiation array 2 is composed of 12 high
frequency radiation units 2x all of which are disposed at the same
axis a1. Of course, this axis a1 is also the first axis a1 of the
low frequency radiation array 1.
Apparently, for high frequency radiation units 2x and low frequency
radiation units 11-15, if they are arranged linearly, then the
pitch between two adjacent low frequency radiation units is not
equal to that between two adjacent high frequency radiation units.
However, it is also required that the pitch between two adjacent
high frequency radiation units 2x is constant and the same applies
to the two adjacent low frequency radiation units 11-15. In this
situation, 3 low frequency radiation units 11, 13 and 15
distributed on odd locations and all high frequency radiation units
12, 14 are arranged commonly on the first axis a1. By this manner,
the pitch between two adjacent high frequency radiation units 2x
arranged on the first axis a1 is a constant value, and pitch
between two adjacent low frequency radiation units 11, 13 and 15 is
necessarily integer times of the above constant value. Assume that
pitch between two adjacent low frequency radiation units 11 and 13
or 13 and 15 arranged on the first axis a1 is 5 times as great as
that between two adjacent high frequency radiation units. Under
this assumption, each of 3 low frequency radiation units 11, 13 and
15 may be concentrically nested with a corresponding one of 3 high
frequency radiation units 21, 22 and 23. Regarding two low
frequency radiation units 12 and 14 arranged at even locations,
pitches among them are equal to those of low frequency radiation
units 11, 13 and 15 located on the first axis a1. In addition, the
two axes a1 and a2 of the low frequency radiation array 1 may be
set to overlap with each other. It can be found that in overlapped
low frequency radiation array 1, all low frequency radiation units
11-15 are located with equal pitch. In other words, for these low
frequency radiation units 11-15 positioned at different axes a1 and
a2, they have definite and same pitch.
Preferably, on an orthogonal projection area formed on the
reflection plate 3, all these nested high frequency radiation units
2x and low frequency radiation units 11-15 are located with their
geometrical centers coincide among each other. For example, in FIG.
6, centers of the low frequency radiation units 11, 13 and 15
overlap corresponding centers of high frequency radiation units 21,
22 and 23 and therefore, orthogonal projection area of the
radiation arm of each high frequency radiation unit falls within
the range of orthogonal projection area of the radiation arm of a
corresponding low frequency radiation unit nested with said high
frequency radiation unit. In addition, these orthogonal projection
areas neither overlap nor cross among each other. The diameter of
low frequency radiation unit is normally large. In present
invention, it is designed to be less than or equal to 150 mm so as
to get optimum setting. Accordingly, person of ordinary skill in
the art will know that this kind of nesting design may be extended
such that orthogonal projection area of the high frequency
radiation unit on the reflection plate falls within the orthogonal
projection area of the low frequency radiation unit on the
reflection plate.
Each of the low frequency radiation units 11, 13 and 15 on the
first axis a1 is nested with a corresponding one of the high
frequency radiation units 21, 22 and 23. Each of the low frequency
radiation units 12 and 14 on the second axis a2 is adjacent to all
the high frequency radiation units 2x. Therefore, on the orthogonal
projection area of the reflection plate 3, it is avoided that
radiation arms (not shown in details, see circles) of the
symmetrical dipole of the low frequency radiation units 11-15 will
be interfered with radiation arms (not shown in details, see cross
line) of the symmetrical dipole of the one or two high frequency
radiation units (interfering means overlapping or crossing of the
images formed on the orthogonal projection area). Therefore, signal
interference between the low frequency radiation array 1 and high
frequency radiation array 2 is reduced mostly, ensuring that signal
transmission and receiving of the low frequency radiation array 1
and high frequency radiation array 2 is independent of each
other.
Each low frequency radiation unit includes two pairs of symmetrical
dipoles all of which are circularly arranged and symmetrical about
a center. As described above, the low frequency radiation array
constructed by said low frequency radiation units 11-15 is located
on the first and second axes a1 and a2 respectively. Take a
symmetrical axis between the first axis a1 and second axis a2 as a
reference line. Each of low frequency radiation units 11, 13 and 13
on the first axis a1 has a symmetrical dipole positioned towards
the reference line and second axis a2. Another symmetrical dipole
is positioned away from the reference line and second axis a2. By
the same token, each of low frequency radiation units 12 and 14 on
the second axis a2 has a symmetrical dipole positioned towards the
reference line and first axis a1. Another symmetrical dipole is
positioned away from the reference line and first axis a1.
Consequently, symmetrical dipoles located inside of the two axes a1
and a2 are adjacent among each other, while those located outside
of the two axes a1 and a2 are distanced among each other. For the
low frequency radiation array located on said axes a1 and a2, the
symmetrical dipoles adjacently located have same or substantially
same signal feed-in power, and the symmetrical dipoles located
outside of the axes also have same or substantially same signal
feed-in power. In addition, the feed-in power of the former is
larger than the latter. By this manner, extension of horizontal
plane beam of low frequency radiation array is achieved.
Another way of extending horizontal plane beam is described below.
Based on above reference line, adjacent symmetrical dipoles located
at one side of the reference line and close to the line has a total
feed-in power same or substantially same as that of the adjacent
symmetrical dipoles located at the other side of the reference line
and close to the same line. Similarly, symmetrical dipoles located
at one side of the reference line and away from the line has a
total feed-in power same or substantially same as that of the
symmetrical dipoles located at the other side of the reference line
and also away from the same line. This ensures that the sum of
feed-in power of the former is larger than that of the latter.
Preferably, the term "substantially same" means symmetrical dipoles
located at two adjacent axes have same signal feed-in power.
However, it is noted that physical error is unavoidable. As such,
person of ordinary skill in the art will understand that the term
"substantially same" also permits adjacent symmetrical dipoles
located at two axes have infinitely approximated signal feed-in
power. Said means for extending horizontal half power beam width of
low frequency radiation array also applies to other embodiments of
the invention.
It is clear that during design phase, it is very important to
arrange location of the low frequency radiation units 11-15 of the
low frequency radiation array 1. In present invention, arrangement
is achieved by following manner. At first, according to axes a1 and
a2, the low frequency radiation units 11-15 of the low frequency
radiation array 1 are arranged to form a temporary array. Next,
adjust size and/or boundary condition of an orthogonal projection
area formed by projecting the low frequency radiation unit of each
temporary array, so that the horizontal plane half power beam width
of the temporary array is larger than a given value. Then, increase
or decrease axis pitch between two adjacent temporary arrays such
that horizontal plane half power beam width of the entire low
frequency radiation array 1 is correspondingly increased or reduced
until it is close or equal to said given value. After the preceding
step is met, the current antenna layout is fixed.
In this embodiment, the high frequency radiation array 2 is
equipped with a feeding network (not shown) for supplying power to
respective high frequency radiation unit 2x located on the first
axis a1 such that the high frequency radiation array 2 is able to
radiate high frequency signals. Also, the low frequency radiation
array 1 is equipped with another feeding network for supplying
power to respective low frequency radiation units 11-15 located on
the first and second axes a1 and a2 such that the low frequency
radiation array 1 is able to radiate low frequency signals. By this
manner, a dual-frequency shared antenna is thus formed. This
antenna has reasonable size, and better electric performance. Pitch
between two adjacent low frequency radiation units of the 3 units
11, 13 and 15 of the low frequency radiation units 11-15 is always
integer times as great as that between two adjacent high frequency
radiation units 2x. Therefore, signal interference among them is
mostly reduced.
Please refer to FIG. 7 illustrating a second embodiment of the
multiple-frequency shared antenna of the invention. In this
embodiment, it is a dual-frequency shared antenna and the
difference of it from the first embodiment lines in 12 high
frequency radiation units 2x of the high frequency radiation array
2 are designed to be distributed along two axes a2 and a3.
More specifically, as depicted in FIG. 7, there are 3 axes a1, a2
and a3. Here, the first axis a1 is shared by partial low frequency
radiation units 1x and partial high frequency radiation units 2x;
the rest high frequency radiation units 2y are separately disposed
on the second axis a2; while the rest low frequency radiation units
1y are separately disposed on the third axis a3. The second axis a2
and third axis a3 are symmetrical about the first axis a1.
Similar to the first embodiment, along axial direction of the axes
a1, a2 and a3, the high frequency radiation units 2x and 2y have
identical axial pitch, and the low frequency radiation units 1x and
1y also have identical axial pitch. In this embodiment however, two
high frequency radiation units 2y corresponding along an orthogonal
direction to each low frequency radiation unit 1x (there are 2
units 1x and accordingly there are 4 units 2y) arranged on the
third axis a3 are biased away from the first axis a1 and disposed
on the second axis a2, thus forming layout as shown in FIG. 7.
The improvement of this embodiment has effect similar to the first
embodiment. However, this embodiment achieves more even and
symmetrical physical construction. Compared to the first one, this
embodiment further reduces horizontal size. In all embodiments of
the invention, the low and high frequency radiation units work on
different frequency range. Here, "low frequency" as occurred in low
frequency radiation unit is relative to the "high frequency" as
used in high frequency radiation unit. Preferably, the low
frequency radiation units work on frequency range of 790-960 MHz
covering 2G and 3G mobile communication frequency bands currently
used all over the world, while high frequency radiation units work
on frequency range of 1700-2700 MHz covering 4 G mobile
communication frequency band such as LTE currently used all over
the world.
Referring to FIG. 8 and according to a third embodiment of the
multi-frequency shared antenna of the invention, a treble-frequency
shared antenna is disclosed. Apparently, compared to the first high
frequency radiation array 2 and low frequency radiation array 1
described in the first embodiment, in this embodiment, a second
high frequency radiation array 4 is added. In addition, the second
high frequency radiation array 4 is provided with power by another
feeding network different from the first high frequency radiation
array 2. The second high frequency radiation array 4 also includes
12 high frequency radiation units 4x arranged along a same axis.
From FIG. 8 it can be seen that the axis a2 of the second high
frequency radiation array 4 is parallel to the axis a1 of the first
high frequency radiation array 2 and overlaps with the second axis
a2 of the first low frequency radiation array 1. Thus, the second
high frequency radiation array 4 is parallel to the first high
frequency radiation array 2. To obtain nesting between the low
frequency radiation unit 1y of the low frequency radiation array 1
arranged on the second axis a2 and high frequency radiation unit 2y
of the high frequency radiation unit 2y arranged on the same axis
a2, start location of the second high frequency radiation array 4
on the second axis a2 is adjusted so that the orthogonal projection
of the two high frequency radiation units 41, 42 on the reflection
plane 3 and that of the two low frequency radiation units 12, 14 of
the low frequency radiation array 1 on the second axis a2 have the
same geometrical center (nesting relationship as described in the
first embodiment). For the multi-frequency shared antenna thus
formed, the first high frequency radiation array 2 and second high
frequency radiation array 4 will be misaligned in vertical
direction. This layout will not have influence on its electric
performance. Therefore, this embodiment is also able to realize
normal signal operation at 3 frequency bands. This ensures that
antenna size is minimized and also ensures that interference among
radiation arrays working different frequency bands is mostly
reduced.
Please refer to FIG. 9. A fourth embodiment of a multi-frequency
shared antenna of the present invention is made upon prior art
technique shown in FIG. 5. The difference between this embodiment
and the third embodiment lies in the pitch between low frequency
radiation units is integer times as great as the pitch between high
frequency radiation units. In the third embodiment, the pitch
between low frequency radiation units is not integer times as great
as the pitch between high frequency radiation units. In this fourth
embodiment, along a direction orthogonal to axes a1 and a2 (lateral
direction in this figure) of the high frequency radiation arrays 2
and 4, the first and second high frequency radiation units 2x and
4x are aligned with each other, thus regularly forming two columns
of matrices. Differently in this embodiment, each of the first and
second high frequency radiation arrays 2 and 4 only includes 10
high frequency radiation units 2x and 4x, while the low frequency
radiation array 1 still maintains its 5 low frequency radiation
units 1x, 1y. Accordingly, the pitch between two adjacent low
frequency radiation units arranged on each axis is still integer
times as great as the pitch between two adjacent high frequency
radiation units 2x, 4x of each of the high frequency radiation
arrays 2 and 4. In this case, on the first axis a1 on which the low
frequency radiation array 1 is located (that is, the axis on which
the first high frequency radiation array 2 locates), 3 low
frequency radiation units 1x are provided, while on the second axis
a2 on which the low frequency radiation array 1 is located (that
is, the axis on which the second high frequency radiation array 4
locates), 2 low frequency radiation units 1y are provided. Each of
the low frequency radiation units 1x and 1y are nested with a
corresponding high frequency radiation in the aforementioned
manner. Along axial direction of the axes a1 and a2, there is just
a location for one high frequency radiation unit between two low
frequency radiation units. In other words, a low frequency
radiation unit nested with another high frequency radiation unit
adjacent to a first high frequency radiation unit is provided. 3
low frequency radiation units 1x is arranged on the first axis a1
at locations 1, 4 and 5 in order, while 2 adjacent low frequency
radiation units 1y is arranged on the second axis a2 at locations 2
and 3 in order. The Multi-frequency shared antenna realized in this
embodiment may also realize normal signal operation at 3 frequency
bands. This ensures that antenna size is minimized and also ensures
that interference among radiation arrays working at different
frequency bands is mostly reduced.
Please refer to FIG. 10. The fifth embodiment of the
multi-frequency shared antenna of the invention is made upon the
third embodiment. In this embodiment of the multi-frequency shared
antenna, a number of low frequency radiation units 1z of the low
frequency radiation array 1 are added on an extending direction of
the respective axes a1 and a2. As denoted by FIG. 10, 5 low
frequency radiation units 1z are disposed above the first and
second high frequency radiation arrays 2 and 4. 4 of these low
frequency radiation units 1z are located on a third axis a3 which
is just a symmetrical axis of the first axis a1 and second axis a2
of the low frequency radiation array 1 as stated in the third
embodiment. The third axis a3 is also the symmetrical axis of the
axes of the first and second high frequency radiation arrays 2 and
4. The rest one of the 5 low frequency radiation units 1z is
directly positioned on the axis a2 of the second high frequency
radiation array 4 (it is also the second axis a2 of the low
frequency radiation array 1). Alternatively speaking, 3 low
frequency radiation units are arranged on the second axis a2 of the
low frequency radiation array 1. In addition, 2 low frequency
radiation units 1y fall within axis range occupied by 4 high
frequency radiation units 4y of the second high frequency radiation
array 4, and are nested with these high frequency radiation units
by the manner described in aforementioned embodiments. The rest one
low frequency radiation unit is located outside of the second high
frequency radiation array 4. Of course, pitch between each two
adjacent low frequency radiation units along the axes a1 and a2 is
identical. Apparently, this embodiment may also obtain technical
effects obtained by preceding embodiments.
Please refer to FIG. 11. A sixth embodiment of a multi-frequency
shared antenna of the invention discloses a five-frequency shared
antenna made upon the third embodiment. In other words, in addition
to the first and second high frequency radiation arrays 2 and 4,
this kind of multi-frequency shared antenna further comprises a
third and fourth high frequency radiation arrays 6 and 8 powered by
separate two feeding networks respectively. The axis a1 of the
third high frequency radiation array 6 overlaps the extension line
of the axis a1 of the first high frequency radiation array 2,
whilst the axis a2 of the fourth high frequency radiation array 2
overlaps the extension line of the axis a2 of the second high
frequency radiation array 2. Partial low frequency radiation units
1x and 1y of the low frequency radiation array 1 are located on the
extension lines of the first and second axes a1 and a2
respectively. Therefore, the total number of the low frequency
radiation units 1x and 1y of the low frequency radiation array 1 is
increased to 10 and these low frequency radiation units constitute
an array and are powered by a same feeding network. Considering
number and location relationship of the low frequency radiation
units 1x distributed on the first axis a1 and resultant electrical
relationship, when the number of the low frequency radiation units
1x within the axis range occupied by the first high frequency
radiation array 2 is 3, the number of the low frequency radiation
units 1x within the axis range occupied by the third high frequency
radiation array 6 will be 2. Similarly, when the number of the low
frequency radiation units 1y within the axis range occupied by the
second high frequency radiation array 4 is 2, the number of the low
frequency radiation units 1y within the axis range occupied by the
fourth high frequency radiation array 8 will be 3. By this manner,
it is ensured that 5 low frequency radiation units 1x and 1y will
be provided on the first and second axes a1 and a2 of the low
frequency radiation array 1 respectively and these low frequency
radiation units are misaligned with each other as described at the
beginning. Each low frequency radiation array 1 is nested with 4
high frequency radiation arrays 2, 4, 6 and 8 and all these arrays
are mounted on the same reflection plate 3. As a result, the
antenna size is significantly reduced and electric performance is
still good.
Please refer to FIG. 12. A seventh embodiment of a multi-frequency
shared antenna of the invention discloses a six-frequency shared
antenna based on the third embodiment. However, this embodiment is
different from the third embodiment in their layout. In the seventh
embodiment, it is formed with side by side arrangement of the
antennae illustrated in the third embodiment. Specifically, it
includes a third and fourth high frequency radiation arrays 6 and 8
parallel to the first and second high frequency radiation arrays 2
and 4 and powered separately by other feeding networks. In
addition, it also includes two low frequency radiation arrays.
Here, the low frequency radiation units 1x, 1y, 1z and 1w are
distributed on at least four axes a1, a2, a3 and a4 overlapping the
axes a1, a2, a3 and a4 of the second high frequency radiation array
2 respectively. The low frequency radiation units 1x and 1y form a
low frequency radiation array working at an independent frequency
band and are powered by a separate feeding network. The low
frequency radiation units 1z and 1w form another low frequency
radiation array working at an independent frequency band and are
powered by another feeding network. Similarly, this embodiment may
also realize small antenna size and get better electric
performance.
It is established from above various embodiments of the invention
that for the multi-frequency shared antenna, multiple low frequency
radiation units of the low frequency radiation array 1 are
distributed on different axes, thus reducing signal interference
between the low frequency radiation array 1 and high frequency
radiation array 2 and maintaining entire size of the antenna
minimized.
The multi-frequency shared antenna of the invention may find its
application in an antenna control system. In this situation,
multiple high frequency radiation arrays 2 and low frequency
radiation arrays 1 are powered by different feeding networks. Each
feeding network contains a phase shifter including first and second
components. Sliding of the first component relative to the second
component results in phase change of signal passing through the
phase shifter, thereby changing phase of the signal provided to
corresponding radiation unit and resulting in tilting of the
antenna beam. To this end, driving force is supplied to the first
component of the phase shifter so as to realize remote control of
the antenna beam tilting.
A well-known method is provision of complex driving construction
inside the antenna. This, however, leads to size and weight
increase of the antenna. To maintain small size, in the present
invention, the antenna control system is provided with a removable
electromechanical driving component. The electromechanical driving
component includes a power control unit, a motor and a mechanical
driving unit. In response to an external control signal, the power
control unit drives the motor to produce a predefined motion.
Through the torque generated by the mechanical driving unit, the
predefined motion of the motor is applied to the first component so
as to realize phase shifting. Accordingly, when it is desired to
tilt beam, the electromechanical driving component may be installed
in the multi-frequency shared antenna and the mechanical driving
unit thereof may act on the first component of the phase shift,
thus achieving beam down-tilting adjustment by external signal
control. When the desired beam tilting angle is met, the
electromechanical driving component may be turned off therefrom
such that respective phase shifters of each feeding networks are
maintained phase stationary. By this manner, beam tilting angle of
the multi-frequency shared antenna is constant.
It is noted that an axis as used herein means a hypothetical line
segment. In addition, overlapping between the axes also permits
slight deviation as known by person of skill in the art. For
example, when a high frequency radiation unit is added onto a piece
of low frequency radiation unit, an axis may be bias a slight
distance from the another axis. As described in the embodiment
shown in FIG. 6, the axis of the high frequency radiation array may
also be biased a distance from the axis of the low frequency
radiation array if the low frequency radiation units are designed
to be of bowl-shaped balun. Accordingly, slight deviation between
two axes is also within the meaning of the term "overlapping" as
defined in this invention. Moreover, the same reasoning also
applies to the term "concentric".
Furthermore, in most cases, the low frequency radiation unit may be
a symmetric dipole which has an orthogonal projection shape on the
reflection plate of diamond, rectangular, polygon or multiple
segments. It may also be a surface mounted dipole or flatly printed
radiation unit. The high frequency radiation unit may be dipole
disclosed in U.S. Pat. No. 6,933,906B2 to Kathrein, Chinese Patent
No.: CN2702458Y to Comba Company or U.S. Pat. No. 7,053,852B2 to
Adrew or other type of dipole.
Furthermore, it is emphasized that preferably the biggest diameter
of the low frequency radiation unit is smaller than 150 mm so as to
further reduce size of the antenna and ensure good electric
performance.
Referring to FIG. 13, an embodiment of the invention also provides
a multi-frequency antenna including a reflection plate 3, a first
frequency radiation array 2x (including 21 and 23) and a second
frequency radiation array (11, 12 and 13). The first frequency is
higher than the second frequency. The second frequency radiation
array (11, 12 and 13) has a first axis a1 and a second axis a2
substantially parallel in a vertical direction to the first axis
a1. It is understood that the axes a1 and a2 are hypothetical to
further illustrate relationship between the first frequency
radiation array and second frequency radiation array on the
reflection plate 3.
The second frequency radiation array includes at least three second
frequency radiation units (11, 12 and 13) located on the first and
second axes a1 and a2 respectively. At least one second frequency
radiation unit is provided on each axis. The three second frequency
radiation units (11, 12 and 13) are misaligned among each other in
a direction orthogonal to the axial direction. Preferably, three
second frequency radiation units (11, 12 and 13) have the same or
similar distance among each other in a direction orthogonal to the
axial direction.
The first frequency radiation array includes at least one first
frequency radiation unit 21 located on the first axis a1.
The second frequency radiation units (11 and 13) on the first axis
a1 are nested with partial first frequency radiation units (21 and
23) on the first axis a1. Reference is made to U.S. Pat. No.
4,434,425 to GTE, U.S. Pat. No. 6,333,720 to Kathrein and Chinese
Patent No.: 200710031144.3 to Comba Company. Clearly, it is well
known in the art to use two different frequency radiation units in
nesting manner. Preferably, in embodiments of the invention, the
nesting may be realized as follows: the orthogonal projection area
of the first frequency radiation unit on the reflection plate falls
within the orthogonal projection area of the second frequency
radiation unit on the same plate. Therefore, in a nested
multiple-frequency antenna, by misaligning the second frequency
radiation units (11, 12 and 13) along a direction orthogonal to the
axial direction, size of the antenna is further reduced.
Consequently, the antenna has reasonable size and better electric
performance as well.
In this embodiment, preferably each second frequency radiation unit
includes two polarization elements each of which includes two
radiation arms. Said two radiation arms may be provided with
different power. Further, each radiation arm is a symmetrical
dipole. Each polarization element of the second frequency radiation
unit has a pair of symmetrical dipoles which can be supplied with
different feed-in power. Using different feed-in power, the
horizontal plane half power beam width of the second frequency
radiation array is regulated. The symmetrical dipoles described in
this embodiment may be those disclosed in U.S. Pat. No. 4,434,425,
6,333,720, or Chinese Patent 200710031144.3.
In this embodiment, preferably, the first frequency radiation array
2x (including 21 and 23) and second frequency radiation array (11,
12 and 13) positioned on the reflection plate 3 are powered by
different feeding networks. The pitch between the first and second
axes is smaller than or equal to the biggest orthogonal projection
size of a single second frequency radiation unit arranged on one of
two axes. It is understood that the biggest orthogonal projection
size means the longest distance between two sides of the projection
perimeter of the radiation unit projected onto the reflection
plate. For a circle projection shape, the biggest orthogonal
projection size is the diameter of the circle; and for a square
projection, the biggest orthogonal projection size is the length of
the diagonal line. It is also understandable that for other regular
or irregular projection shape, the biggest orthogonal projection
size is the smallest diameter of a circle which encircles the
irregular projection shape. Therefore, the present invention is
adapted to specific used frequency requirement.
In this embodiment, preferably a symmetrical axis a3 is defined
between the first and second axes. Two low frequency radiation
units of all the second frequency radiation units positioned on
different axes form a group. Regarding four symmetrical dipoles of
the same polarization in the group, symmetrical dipoles close to
the symmetrical axis a3 have the same or similar feed-in power, and
those away from the symmetrical axis a3 also have the same or
similar feed-in power. In addition, feed-in power of those dipoles
close to the symmetrical axis a3 is greater than that of the
dipoles away from the symmetrical axis a3. By above setting, the
horizontal plane half power beam width of the second frequency
radiation array is further widened, and left and right symmetry of
the horizontal direction pattern is also guaranteed.
In this embodiment, preferably nesting use of the second frequency
radiation unit on the first axis and partial first frequency
radiation units on the same axis is as follows: the second
frequency radiation has its geometrical center overlapped that of
at least one first frequency radiation unit.
In this embodiment, preferably nesting use of the second frequency
radiation unit on the first axis and partial first frequency
radiation units on the same axis is as follows: the orthogonal
projection area of the high frequency radiation unit on the
reflection plate falls within that of the low frequency radiation
unit on the same plate.
In this embodiment, preferably in the multi-frequency shared
antenna provided by embodiments of the invention, the second
frequency radiation array also includes a third axis running as a
symmetrical axis of the first and second axes. The second low
frequency radiation units are located on this symmetrical axis.
In a summary, by making improvement on layout of the
multi-frequency shared antenna, the antenna is benefited from
reasonable size, and better electric performance. Further,
relationship between linear arrangement pitch of the low frequency
radiation units and that of the high frequency radiation units is
no longer a critical factor having heavy influence on design of
antenna layout by person of skill in the art.
The antenna size is more reasonable because of the following
reasons.
In case that pitch among low frequency radiation units arranged on
the same axis is not integer times as great as that of the high
frequency radiation units, by placing different low frequency
radiation units of the same low frequency radiation array on two or
more axes, interference (overlapping or crossing) among low
frequency radiation array and high frequency radiation array in the
orthogonal projection area is avoided, thus signal transmission of
the low and high frequency radiation arrays will not interfere with
each other, thereby eliminating or reducing mutual
interference.
In case that pitch among low frequency radiation units arranged on
the same axis is integer times as great as that of the high
frequency radiation units, for example in case where three
frequencies present and at least two of them are identical high
frequency arrays, compared to solution in which a group of high
frequency radiation arrays is added in a vertical direction of the
antenna, use of the present invention not only avoids increase of
transfer loss caused by lengthening of the main feeder line of the
upper high frequency radiation arrays, but also obtain increase of
antenna gain. Moreover, when the length of the low frequency
radiation array is smaller than integer times of the length of the
high frequency radiation array, the entire length of the antenna is
dramatically decreased. Compared to adjoining technical solution,
use of the invention also reduces width of the antenna. Further, as
the low frequency radiation units are arranged in a misaligned
manner in a direction orthogonal to the axis, symmetry between left
and right radiation boundary of the low and high frequency
radiation arrays is improved. Antenna design difficulty is also
reduced.
Though various embodiments of the invention have been illustrated
above, a person of ordinary skill in the art will understand that,
variations and improvements made upon the illustrative embodiments
fall within the scope of the invention, and the scope of the
invention is only limited by the accompanying claims and their
equivalents.
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